Hot extrusion machine

ABSTRACT

A machine for producing metal tubes by hot extrusion of billets. The machine has an annular extrusion gap, a plurality of containers for receiving billets which are uniformly angularly spaced about the extrusion gap and grooves or conduits formed in an annular plate of progressively diminishing cross section towards the annular gap for channeling metal from the billets as associated extrusion pistons exert pressure on the ends of the billets remote from the extrusion gap, the grooves or conduits being delimited by an extrusion needle arranged coaxially of the extrusion gap.

United States Patent [191 Creuzet Jan. 22, 1974 HOT EXTRUSION MACHINE Primary Examiner-Charles W. Lanham Assistant ExaminerRobert M. Ro ers 76 Inventor: Robert Armand Creuzet Route de g 1 Beyssac, Marmande prnce Attorney, Agent, or FirmKarl F. Ross; Herbert 22 Filed: Feb. 16, 1972 Dubn" 21 A 1. No.: 226 829 1 pp 7 57 ABSTRACT [30] Foreign Application Priority Data A machine for producing metal tubes by hot extrusion Mar 26 1971 France 7110820 of billets. The machine has an annular extrusion gap, a plurality of containers for receiving billets which are [52] U 5 Cl 72/259 72/269 uniformly angularly spaced about the extrusion gap [5] I B21c 23/00 and grooves or conduits formed. in an annular plate of [58] Field 258 269 progressively diminishing cross section towards the annular gap for channeling metal from the billets as asso- [56] References Cited ciated extrusion pistons exert pressure on the ends of the billets remote from the extrusion gap, the grooves UNITED STATES PATENTS or conduits being delimited by an extrusion needle ar- 2 1 11; llvterrie 72/258 ranged coaxially of the extrusion gap.

, ones 10 Claims, 4 Drawing Figures PATENTEUM 22 m4 SHEET 1 If HOT EXTRUSION MACHINE The invention concerns the manufacture of metal tubes by high temperature extrusion. In order to produce a metal tube by hot extrusion a metallic mass or billet at a suitable temperature is subjected to a sufficiently high pressure on one of its faces so that the metal flows through an annular gap provided by a die head and a central needle.

In order to channel the metallic mass which flows from the whole transverse section of the billet towards the annular peripherical portion it has been proposed to interpose in the circulating metal flow a deflector or bridging member for spreading the mass and directing it towards the said gap.

This bridge is subjected to very large forces which prevents the formation of tubes of a diameter greater than a predetermined value although tubes of a greater diameter are also desirable.

The invention obviates this limitation and consists in a machine for producing metal tubes by hot extrusion from a plurality of metal billets having cross-sectional diameters which are not necessarily related to the diameter of the tubes tobe produced and which, in practice, is considerably smaller than that of the tube, said billets being regularly disposed about the axis common to the head and the extrusion needle and subject to the simultaneous action of extrusion pistons on their ends opposite to those facing the annular gap, conduit means being interposed between the flowing ends of the billets and the annular gap where the various flows merge into a single flow corresponding to the tube to be formed by extrusion.

In the description which follows, made by way of example, reference will be made to the accompanying drawing, in which:

FIG. 1 is a schematic view in perspective of a part of a machine according to the invention, certain of the parts having been omitted;

} FIG. 2 is a partial front view;

' FIG. 3 is a sectional view'along line 3-3 of FIG. 2;

and

FIG. 4 is a sectional view along line 4-4 of FIG. 2.

of the billets to a temperature suitable for extrusion.

In the rear portion of the cups, extrusion pistons 14,-14 bear against the rear faces 15,45 of the billets and may be urged forwardly responsive to corresponding displacements of one or more hydraulic jacks (not shown).

The forward orifices 16,-16 of the cups or containers are closed off by a rim 21 (FIGS. 2-4) of a ring or disc 22 coaxial with the group of the containers 12,42 and one or more conduits or grooves facing each container 12 (two in number in the illustrated embodiment) 23a, 23b extend from the rim 21 and are joined at their other ends to a collar 24 provided on disc 22 thereby defining with the extrusion needle 25 an annular gap 26 of a progressively diminishing section from rear to front. The extrusion needle 25 is advantageously displaceably mounted, for example by threads 27 on the body 28 where the cups 12 are arranged. Therefore by changing the needle different extrusion gap heights may be obtained.

The collar 24, in longitudinal section, has at its portion 29 a relatively slight'slope and then towards its forward edge at 30 a more accentuated slope until it reaches the cylindrical surface 31 forming the extrusion gap 33 per se with the cylindrical outer surface 32 of the needle 25.

When the extrusion thrust is exerted simultaneously on the rear faces .15 of the billets 14 which are at a suitable temperature, the metal of the billets flows in the grooves 23 towards the axis 11, fills the gap 26 of diminishing section and then flows through the extrusion gap 33 as shown by the shaded portion, the pressure of the metal flowing in the said gap being sufficiently great to have the edges of the partial flows coming from the various containers or cups join in a continuous manner so that the metal flows through the extrusion gap 33 is effected under the same conditions as during hot extrusion starting with a single billet.

The apparatus is, however, free of bridges provided in known apparatus for spreading metal coming from a single billet disposed coaxially of the extrusion gap which the metal deflects towards the entrance to the said gap along one or more passages.

What is claimed is:

l. A hot extrusion machine for producing metal tubes, comprising an annular extrusion gap, a plurality of containers for receiving billets regularly angularly spaced about the annular gap, and means for channeling the flow of metal from the billets towards the annular gap as an extrusion pressure is exerted on the ends of the billets remote from the annular gap, the channeling means comprising conduits converging towards the extrusion gap, a plurality of such conduits being provided between any one of the container and the annular gap.

2. A machine according to claim 1, further comprising an extrusion piston associated with each container for exerting the extrusion pressure on its associated billet.

3. A machine according to claim 2, wherein the pistons move in unison.

4. A machine according to claim I, wherein the conduits have progressively diminishing cross sections towards the extrusion gap.

5. A machine according to claim 1, wherein the conduits are formed in a single annular plate.

6. A machine according to claim 5, wherein the conduits are delimited by a central extrusion needle.

7. A machine according to claim 6, wherein the extrusion needle is removably mounted relative to said annular plate.

8. An apparatus for the extrusion of a metal tube, comprising a plurality of cylinders having parallel axes; and angularly equispaced about a central axis; a respective piston received in one end of each of said cylinders for driving a billet of metal within the cylinder and individual thereto in the direction of its other end; a needle disposed along said central axis at said other ends of said cylinders; an annular die surrounding said needle and coaxial therewith to define an annular passage through which metal of said billets is extruded to form the tube; and at least one channel communicating between each cylinder at its other end and said passage and incline to a plane perpendicular to said axis and to direction of said passage.

10. The apparatus defined in claim 8 wherein said cylinders are formed in a common body and said needle is removably mounted in said body. 

1. A hot extrusion machine for producing metal tubes, comprising an annular extrusion gap, a plurality of containers for receiving billets regularly angularly spaced about the annular gap, and means for channeling the flow of metal from the billets towards the annular gap as an extrusion pressure is exerted on the ends of the billets remote from the annular gap, the channeling means comprising conduits converging towards the extrusion gap, a plurality of such conduits being provided between any one of the container and the annular gap.
 2. A machine according to claim 1, further comprising an extrusion piston associated with each container for exerting the extrusion pressure on its associated billet.
 3. A machine according to claim 2, wherein the pistons move in unison.
 4. A machine according to claim 1, wherein the conduits have progressively diminishing cross sections towards the extrusion gap.
 5. A machine according to claim 1, wherein the conduits are formed in a single annular plate.
 6. A machine according to claim 5, wherein the conduits are delimited by a central extrusion needle.
 7. A machine according to claim 6, wherein the extrusion needle is removably mounted relative to said annular plate.
 8. An apparatus for the extrusion of a metal tube, comprising a plurality of cylinders having parallel axes; and angularly equispaced about a central axis; a respective piston received in one end of each of said cylinders for driving a billet of metal within the cylinder and individual thereto in the direction of its other end; a needle disposed along said central axis at said other ends of said cylinders; an annular die surrounding said needle and coaxial therewith to define an annular passage through which metal of said billets is extruded to form the tube; and at least one channel communicating between each cylinder at its other end and said passage and incline to a plane perpendicular to said axis and to the axis of its cylinder toward said passage in the direction of flow of the metal of the billet.
 9. The apparatus defined in claim 8 wherein two such channels are provided between each cylinder and said passage, the channels of said cylinders diverging in the direction of said passage.
 10. The apparatus defined in claim 8 wherein said cylinders are formed in a common body and said needle is removably mounted in said Body. 